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Fuel Pressure & Other Weird Issues

GOTIT4CHEAP16

GOTIT4CHEAP16

New member
LTFT thread i made last week http://www.grandprixforums.net/ltft-aeroforce-gauge-51820.html

Okay so ive been having some problems with me car like surges at idle, weird ltfts etc. I went and bought a fuel pressure gauge this morning from advanced and hooked it up but i got nothing when i turned the car on or cranked it up. No pressure at all. ZZP modded fuel rails installed.

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When the car was on i was also seeing small white smoke but was only for a few seconds
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Dont know what else to do. Also this is a new engine with 53k miles on it because my last engine had a cracked flex plate but sits in my garage at the moment. I had to swap my i/c lim over to the new one along with the supercharger so i changed the LIM Gaskets with the new aluminum ones from advance auto parts.

My LTFT'S are still weird and off and in the positives but i dont know where sle to check for a vacum leak..?? I checked the PCV and it is fine and gasket is still on it, i have AL104's gapped to .55 brand new, checked all the vacuum lines and they are good and not cracked. And if it helps, i have a ZZP modded fuel rail installed on the car. I still have my stock FPR also.
 
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is the gauge hooked up correctly? if it is running i would expect some pressure...

what is the pressure with the engine off and key on? if you disconnect the vac line to the fuel pressure reg does the pressure change?
 
Yes i read the instructions before hooking it up. With the engine on and off, i still didnt see an pressure or change from the gauge. Didnt try with the vacuum line off but i will try and reply.
 
If your not leaking gas when you take it off u don't have it on tight enough. It looks like the gauge I have. It will go o. Loose then get tight as u start to depress the schrader valve. You could always go back to where u bought it and show them... Maybe it is a bad gauge?
 


Yea i hooked it up right according to the manual. When I took the cap off the rail, I had a rag underneath and fuel spilled out so I had to slowly untwist the cap so that should indicate that I have pressure and it could be the gauge. I will double check tommorow morning and if it.still doesn't work then ill take it back.to.advanced and get a replacement.
 
Somethings not right if the car is running and your fuel pressure gauge is reading "0". Either your gauge is hooked up wrong or broke. If you have gas in it when you take it off and it's tight, it may be broken.
 
So this morning i plugged in my Obd2 scanner and got some live data after some driving and heres what i got. What does all this mean? Good or bad?

Coolant Temp: 179 F
STFT - Bank 1: 1.5%
LTFT - Bank 1: 16.3%
Manifold Pressure: 8.7 in. hg
Engine RPM: 819 RPM
Vehicle Speed: 0 mph
Ignition Advance: 27.0 deg
Intake Air Temp: 131 F
MAF Air Flow Rate: 0.5 lb/min
Throttle Position: 0.3%
Bank 1 - Sensor 1: 02s output 0.55v
Bank 1 - Sensor 1: 0.0%
Bank 1 - Sensor 2: 02s output 0.450v
Bank 1 - Sensor 2: 99.0%
 


the only thing that tells much about your car from that slice of data is the LTFT's being +16% that means your car is adding 16% more fuel at that current condition. so what ever yoru MAF is you need to go into that area and increase it 16% for those few Hz cells my guess is it is 2750 hz. so increase that area 16% and for 2500 only 10% and for 3000 10% i always try and graph my spark and Maf tables to smooth them out... any sharp changes mean there is either an error or something not right....a sharp change in fuel or spark can cause detonation which leads to KR.

GOTIT4CHEAP16 said:
So this morning i plugged in my Obd2 scanner and got some live data after some driving and heres what i got. What does all this mean? Good or bad?

Coolant Temp: 179 F
STFT - Bank 1: 1.5%
LTFT - Bank 1: 16.3%
Manifold Pressure: 8.7 in. hg
Engine RPM: 819 RPM
Vehicle Speed: 0 mph
Ignition Advance: 27.0 deg
Intake Air Temp: 131 F
MAF Air Flow Rate: 0.5 lb/min
Throttle Position: 0.3%
Bank 1 - Sensor 1: 02s output 0.55v
Bank 1 - Sensor 1: 0.0%
Bank 1 - Sensor 2: 02s output 0.450v
Bank 1 - Sensor 2: 99.0%
Click to expand...
 
Your vacuum is way low should be around 18 inch hg. At idle.. I suspect a vacuum leak which is why your ltfts are pegged out at 16%...
 
Guess i will be redoing my LIM and actually using a torque wrench this time. What kind of torque wrenches did you guys use and would recommend?
 
Before you go that far, confirm it's not a vacuum line or the egr tube. Spray some carb cleaner around the top of the engine and if idle changes you found your leak. I got my torque wrench from napa, it was around $100. You can find cheap ones for around $20 but I wouldn't trust the accuracy.
 
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GOTIT4CHEAP16 said:
Guess i will be redoing my LIM and actually using a torque wrench this time. What kind of torque wrenches did you guys use and would recommend?
Click to expand...

well you probably found your vac leak...

go to sears and get a craftsman one. you only need the one that does up 75-80 ft lbs for working on the lim. just the regular one will do fine. husky brand ones at home depot are good too and i think a little cheaper than craftsman.

every bolt on you motor should be torqued to spec. theres a few small things that you can get away with without the torque but things like the lim and SC need to be torqued!

exhaust leaks can throw the o2 readings off and show you running lean too. make sure you dont have any leaks, especially before the o2. a custom tune could also fix all these problems too. i have no leaks and my ltft sit at 16.4 at idle and jump all over place because i havent tuned my maf yet.

and dont chip a piston while your running lean.
 


My egr is deleted using the zzp mod and i tried carb cleaner and didn't notice any changes at all. My bluetooth obd2 connector came in yesterday and i connected it to my android phone and my vacuum stayed around 19-20 hg @ idle according to the torque app. Isnt that normal? After seeing that im starting to doubt that my lim could be the problem. But i will still pull my supercharger and torque down the bolts though instead of redoing them.

Swiggles, my ltft's doesn't always sit on 16.4 @ idle its is sometimes at around 8,9,13,3.9,4 etc. and also jumps all over the place. Im not getting any codes on the car other than a p0446 (evap) code. No 1 single lean code at all. Ive cleaned the Maf sensor also.
 
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ya thats where your vac should be so no leak. your problem is the tune. try to find someone in your area, and its worth a 2-3 drive to the right person to do it, and have them tune it.
 
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